The task of these artillery officers or N. C. O. is:— (1) To control all means of communication with the batteries of the artillery support. (2) To transmit to the artillery the different calls for fire, and in technical terms to give the proper data for the laying of the pieces on the target, and the kind of fire required. =Use of Artillery Support.= Different kinds of fire are executed by the artillery support. The most important is the barrage. =Barrage.= Purpose:—The purpose of a barrage is to stop a hostile attack before it can get started, or to hinder enemies’ reinforcements or reserve troops from coming forward. Form:—The barrage is a curtain of fire let down in “No Man’s Land” as close in front of your first line as possible without loss to your own garrison. This will be about 150 or 200 yards to the front, between the two lines of trenches. [Illustration: LOCATION OF ARTILLERY FOR BARRAGE] Front of the Barrage:—The barrage has real value only if it is impassible. This will be if the density of the fire is so great that the danger zones of the explosions of the individual shells overlap each other. The allotting of one troop of artillery, 12 guns, for an infantry battalion is quite sufficient for this purpose if the front of the battalion does not exceed the average length of from 400 to 600 yards. Duration:—The barrage is a burst of fire which lasts from six to ten minutes. At the beginning the fire is very rapid and towards the end becomes slower. For instance, for the first six minutes the fire may be six rounds per gun and in the last four minutes, say, four rounds per gun. Successive barrages can be carried out depending upon the needs of the infantry. Calling for the Barrage:—Barrage fire, for the best results, must open up at the moment the hostile attack begins. To accomplish this the call for the barrage must be made by an observer in the first line. For this reason every officer in the first line has the authority to call for the barrage. The barrage is the only fire that can be called for automatically by signal. The kind and color of the rocket signifies the type of barrage required and the front it is to cover. In order to avoid mistakes this rocket signal is repeated from some point farther to the rear, usually at the observatories of the command post of the center of resistance, or of the sector. Rocket signals are repeated until the barrage fire opens. Confirmation of the barrage is given by telephone, if possible. However, at the first signal rocket the artillery is required to open up the barrage fire as quickly as possible without waiting for confirmation. Barrage fire is at the disposal of the infantry and cannot be refused by the commander of the artillery, whether it is justified or not. =Other Kinds of Artillery Fires.= The commanders of the center of resistance or of the sector may call on the artillery support for other fires besides the barrage, such as: Reprisal fire on the enemy’s lines.